Coat-tail

Do not always ride on someone's coat-tail.

Source: tatoeba (269970)

At twilight in the summer […] the mice come out. They […] eat the luncheon crumbs. Mr. Checkly, for instance, always brought his dinner in a paper parcel in his coat-tail pocket, and ate it when so disposed, sprinkling crumbs lavishly—the only lavishment of which he was ever guilty—on the floor.

Source: wiktionary

He paced the floor uneasily, his hands under his coat-tails.

Source: wiktionary

He could merely urge his heavy bulk onward toward the fast fleeing train; and dashed up the platform, overcoat streaming from his arm, coat-tails flying, hat crushed down upon his head, his fat, bechalked legs rumbling heavily after him.

Source: wiktionary